Handle context concelation during ingestion

[gammazero]

In some places context cancelation was not handled during ingestion. This caused the indexer to be unresponsive to a shutdown request. This change will include context cancelation when selecting to read or write channels.

Adds additional debug logging.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 82.85714% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 44.73%. Comparing base (021ab38) to head (e35cb13).

Files	Patch %	Lines
internal/ingest/linksystem.go	77.77%	4 Missing ⚠️
internal/ingest/ingest.go	88.23%	2 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2592      +/-   ##
==========================================
+ Coverage   44.63%   44.73%   +0.10%     
==========================================
  Files          95       95              
  Lines       11268    11296      +28     
==========================================
+ Hits         5029     5053      +24     
- Misses       5635     5639       +4     
  Partials      604      604              

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